When distributing electricity underground, cable joints are commonly used to make multiple cable connections. One type of joint that is used at secondary voltages (600 volts or lower) is a permanent, rubber molded product having lengths of a cable (“pigtails” or “legs”) connected to a copper bus that makes up the conducting element of the joint. During installation, the splicer installs the joint by compressing one end of a copper tube on the cable pigtails and the other end of the copper tube on the cable. The connection is then insulated using tape, a rubber sleeve or a piece of heat shrink insulation.
Joints can typically connect up to 7 cables on each side. Each pigtail is called a “leg.” Each leg can include an integral fuse section. Like any fuse its purpose is to interrupt faults. In the prior art joints, for 120/216V applications, the fuse is a section of the bus of the joint with a smaller cross section than the rest of the bus. That smaller cross section will heat up faster than the rest of the bus. When a certain amount of current flows through that smaller section, the copper will melt, interrupting that leg.
One drawback of the commonly available 120/216V pigtail joints is that the fuses are not individually replaceable. As such, if a fuse blows on a leg the connection is disrupted and that leg becomes useless. The leg is therefore usually cut off and the cable that was connected to that leg is then connected to a fresh leg. Once all the legs become useless, or if the joint can no longer provide enough connections, the joint is often cut out and replaced. Accordingly, it is common practice to use a joint having more legs than necessary.
The joint is typically rubber molded in its entirety to seal against water ingress. This can cause other drawbacks. For example, with the prior art joints it can be difficult to tell if one or more of the fuses has blown without making contact with the cable on each side of the fuse.
Accordingly, it is desirable to provide a joint that overcomes these and other drawbacks of the joints currently available in the market.